Telescope Reviews: Amazing videos of Meteor in Russia!

That is because any meteors from 2012 DA14 would have a *very* specific radiant very close to the south celestial pole (R.A. 149°, Dec -81°!). This means that any meteoroids with orbits that are similar to 2012 DA14 would be approaching the Earth almost exactly from the south. This is a very fortunate circumstance that allows quick distinction between possibly related and certainly unrelated events. There is much talk about the Earth gravitationally capturing, deflecting and redirecting the Russian meteoroid so that it somehow managed to change directions and come from the direction it did. There indeed is some ‘gravitational focusing’ of meteoroids by the Earth. In meteor astronomy its effect is call zenith attraction. As the meteoroid approaches the Earth it is being ‘pulled in’ and its approach angle becomes steeper. This is especially notable with slow meteoroids. In effect this means that a meteoroid can enter the atmosphere at locations where its radiant is below the horizon – it arcs from a trajectory tangential to the Earth into an intercepting trajectory. A well known meteor astronomer did a short calculation of the zenith attraction for any possible meteoroids from 2012 DA14 and the highest latitude where a meteoroid could enter the atmosphere was 55° N (here it would be on a tangential, grazing trajectory). Chelyabinsk is at 55° N. However, at the time of the Russian meteor this point was on the opposite side of the northern hemisphere (due to the 9° approach angle from the south). Also, the Russian meteor’s atmospheric trajectory had an angle of ~15-20° to the surface, while any meteor from 2012 DA14 would have an extremely shallow grazing trajectory. Furthermore, the Russian meteor came in from ENE, while 2012 DA14 meteoroids come in directly from the south. Not related. In any case, orbit calculations take all these effects into account and clearly the two orbits are not related.

Regarding other fireballs at the time. There is a video of a bright evening fireball over Russia (in fact, only about 700 km west of Chelyabinsk!) on Feb 12. But it clearly fell at a very steep angle, so its radiant was most probably in the northern celestial hemisphere. Not related. The Feb 15 Cuba meteor is very dubious with no videos and very few (if any) eyewitness reports. At its supposed magnitude, it should have been seen over a very large area by many people. The Feb 14 Japan fireball (which is not really very large anyway) has a different orbit, although both are Apollo-type orbits with aphelia in the main asteroid belt. The Feb 15 California fireball (which is even smaller) requires a slightly more detailed analysis of the video and eyewitness reports, so not sure about that one.

There is, apparently, at least one confirmed Near-Earth Asteroid and meteorite-dropping fireball association: http://www.spmn.uji.es/ESP/articulo/2002NY40_MNRAS.pdf